There are many previously known devices for positioning tools, welding guns and the like for mass production machining and assembly operations.
Some previously known lift and carry workpiece transfer mechanisms have used a so-called Watts linkage drive to raise and lower the workpieces.
A Watts linkage is a three link kinematic mechanism which has three long links pivotally connected together at adjacent ends with the remaining ends of two of the links pivoted about spaced apart and fixed pivot points. The links are constructed and arranged with a geometry that produces an essentially linear reciprocating motion of the center of the middle link. It is well understood that in a Watts linkage the links must be relatively long to produce this linear motion.
Because the links do not move in a true straight line, a Watts linkage is not driven or powered by an actuator producing a straight line or rectilinear motion.